The present invention relates to an apparatus for drying pistachio nuts during processing.
Pistachio nuts have a hard shell around the edible nut and a pericarp or hull which encases the shell. The hull of unripened pistachios adheres strongly to the shell and is difficult to remove whereas the hull is relatively easily removed from ripe pistachios. It is necessary to mechanically hull pistachios in order to process commercial quantities of the nut. Once hulled, blanks may be separated from the pistachios by immersing the pistachios in a flotation tank and allowing the good pistachios to sink and be collected. These pistachios should then be partially dried for further processing.
In general term, the invention provides a method and apparatus for drying and conveying pistachio nuts or other small objects. The pistachios are deposited onto a plurality of moving and fixed plates or trays. The moveable plates are interleaved with the fixed plates. All plates are inclined and slotted. The moveable plates reciprocate back and forth, pushing the pistachios to one end of the apparatus. At the same time, heated air is forced through the plates to dry the pistachios.
Therefore, in one aspect, the invention comprises an apparatus for drying and conveying small articles such as pistachio nuts comprising:(a)a plurality of inclined, interleaved fixed and moveable planar plates, wherein each plate: (1) overlaps an adjacent plate and is parallel to the adjacent plate; (2) defines a plurality of openings which are smaller than the article to be dried and conveyed; (3) wherein moveable plates are moveable along a plane parallel to the plane of an adjacent fixed plate; (b) means for reciprocating the moveable plates; and(c)means for blowing air through the plates.
The apparatus further comprises an air plenum beneath the plates for directing heated air through the plates. In one embodiment, the plates are rectangular. The plate reciprocation means may comprise a substantially horizontal elongate beam which is reciprocated horizontally, wherein each moveable plate engages the beam, at least one ramp supporting the beam and having an angle of inclination substantially equal to angle of inclination of the plates and means for reciprocating the beam. The beam reciprocation means may comprise a reciprocating shaft operatively connected to a motor by means for translating rotational movement to horizontal movement.
The motion translation means may comprises a circular disk having a non-central pin, a vertical channel engaging the pin, wherein said vertical channel engages the reciprocating shaft.